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POPULAR SCIENCE MONTHLY 



much more like that of the forest region of the eastern states than any 

 part of Colorado to-day. After working at Florissant in the summer 

 of 1907, I had occasion to spend some time at Garrison-on-Hudson, 

 and as I daily went through the splendid woods of that region, it 

 seemed to me as if the flora of the shale had come to life. There was 

 the sweet fern, Comptonia, to-day confined to a single species of the 

 eastern United States; in Miocene times wide-spread, and represented 

 by two kinds at Florissant. There was the large-toothed aspen; 

 leaves with even larger teeth, but very similar, were found in the shales. 

 Then the chestnut — great chestnut leaves, of an undescribed species, 

 were among the best of our finds. So also the basswood, the walnut, 

 the ironwood, elm, hickory, holly and many other trees, now wholly 



Fossil Febn (Phcgopteris guyottii). 



absent from Colorado, but common to the Miocene shales and the east- 

 ern states. One of the most interesting of the fossils is the sweet-gum, 

 or Liquid ambar; a genus widely dispersed in the Miocene, from America 

 to Europe, while now its few scattered remnants are found in our 

 Atlantic coast region, in Mexico and Central America and in Asia. 

 On the other hand, the existing Eocky Mountain flora is represented 

 in the Florissant shales by species of oak, alder, birch, hackberry, bar- 

 berry, mock-orange or Philadelphia, maple, gooseberry, grape, rose, 

 hawthorn, mountain ash, willow, Virginia creeper, sumach and a num- 

 ber of others, showing that with all the change of climate which has 

 occurred, the flora has not been totally transformed. 



No recognizable mammal has been obtained at Florissant; only a 



